Prenatal Exposure to Tobacco Linked to Shorter Fetal Telomere Length

(HealthDay News) — Prenatal exposure to tobacco is associated with shorter fetal telomere length, according to research published in the February issue of the American Journal of Obstetrics & Gynecology.

Hamisu M. Salihu, M.D., Ph.D., of the University of South Florida in Tampa, and colleagues administered a self-report questionnaire and salivary cotinine test to confirm tobacco exposure in pregnant women admitted to the hospital for delivery. Genomic DNA from neonatal umbilical cord blood was analyzed to assess fetal telomere length. The ratio of relative telomere length was determined by the ratio of telomere repeat copy number to single copy gene copy number (T/S ratio).

The researchers found that smoking was inversely related to fetal telomere length in a dose-response pattern. T/S ratio was greater in descending order in nonsmokers, than in passive smokers, than in active smokers. For each pairwise comparison, significant differences were observed in telomere length. The greatest difference in telomere length was found between active smokers and nonsmokers.

"Our results provide the first evidence to demonstrate a positive association between shortened fetal telomere length and smoking during pregnancy," the authors write.